A defamation case laid by ACC Minister Judith Collins against Labour MPs Andrew Little and Trevor Mallard has been set to go to trial, however, it could still be resolved by a Privacy Commissioner's investigation into a leaked email about an ACC client.

Ms Collins has taken legal action against the pair for alleging she or her office leaked an email, sent from former National Party president Michelle Boag to Ms Collins, to media.

The email gave details about Bronwyn Pullar, the ACC claimant who went to the media earlier this year after being mistakenly sent details of almost 7000 ACC claimants.

A preliminary hearing was held in the High Court at Auckland this morning and a trial date was set for three to five days in February next year.

A settlement conference has also been set down November when the matter could still be resolved outside of court.

Counsel should by that time have a report by Privacy Commissioner Marie Shroff, who is currently investigating how the email got to the media.

The majority of today's court hearing cannot be reported, other than the directions given by Justice Geoffrey Venning.

He declined an application by the defendants' counsel, John Tizard, to have the proceedings delayed pending the outcome of the Privacy Commissioner's report, which Mr Tizard had submitted could be "critical''.

Justice Venning said the report may not be determinative, and the court would not be bound by its findings.

The trial is set to be before a judge alone, however, Justice Venning reserved the defence's right to seek a jury in light of the report.

He said the key issues in the case were whether the comments made by Mr Little and Mr Mallard were on an occasion of qualified privilege; whether they were motivated by ill will; and whether they took improper advantage of the circumstances.

Mr Little and Mr Mallard maintain they have not defamed the ACC Minister.

"As an opposition MP, I am required to hold ministers to account for their conduct and decisions,'' Mr Little said outside court in April.

"The matter is a political one and that is the arena in which it should remain. [Ms Collins] has ample opportunity to answer questions about the issue in the public arena and to defend her actions, as I would mine.

"Suing political opponents who raise legitimate questions is no way to advance or resolve such an issue.''